Circuit breaker



9, 1935- L. B. CHUBBUCK ET AL 2,021,499

C IRCUIT BREAKER Filed April 24, 1934 5 Sheets-Sheet 1 INVENTORS.Lafiard B C/ZL/buc/t, George/ Wis/m7? (i Weak;

WITNESSES ATTOR EY Nov. 19, 1935. B, CHUBBUCK Er AL 2,021,499

CIRCUIT BREAKER Fil ed April 24, 1954 5 Sheets-Sheet 2 Leo/70 x2 3.C/n/bfiuck, George 1?. Wis/mm 4i lf 'en L. L Jeppesew.) KW MQ TTOR YNov. 19, 1935. L. B. cHuBBucK-ET AL 2,021,499

CIRCUIT BREAKER Filed April 24, 1934 5 Sheets-Sheet 3 ATTORN PatentedNov. 19, 1935 UNITED STATES PATENT orrics 11 Claims.

Our invention relates generally to electrical apparatus and it hasparticular relation to circuit breakers which are used for opening andclosing electrical power circuits.

The object of our invention, generally stated, is to provide a circuitbreaker having a motoroperated closing mechanism which shall be simpieand eflicient in operation and which may be readily and economicallymanufactured and installed.

The principal object of our invention is to provide for connecting amotor to the movable contact members of a circuit breaker.

Another object of our invention is to provide atrip' free connectionbetween a motor-operated closing mechanism and the movable contactmembers of a circuit breaker.

A further object of ourinvention is to provide for preventing theau'tgnnaticreclosure of a" cir'- cuit' breaker after it has operatedonce, while the closing switch is held the operated 1308ition.

A Still further object or our invention is' to provide for operating acircuit breaker by" means of a motor and mechanically'and electrically"oper'ated clutches connected in series between the motor and the movablecontact members or the circuit breaker.

Other objects of our invention will in be obvious and in part a'p'pearhereinafter.

Our invention accordingly is disclosed in the embodiment hereof shown inthe accompanying drawings" and comprises the features of construction',combination or" elements, and arrangementof parts which will beexemplified in the construction hereinafter setforth, and the scope ofthe application of which will be indicated in the appended claims.

For a more complete understanding the nature and scope of our invention,reference may had to the-following detafled' descripfidn, takenconnection with the accompanying drawings; in which-z Figure 1 is aview, partlyin' side elevation and partly in section, illustrating aconcrete embodiment' of our invention; t

Fig. 2 is an enlarged view, partly in; section, showing a part of themotor-operated mechamam;

Fig. 3' is a view; partly n side elevation and partly in section, takenalong the line III -III* of Fig. 4; showing detailsof constructioiroithe" motor-operated mechanism; v o

Fig. 4 is a sectional view taken along the line IV IV' of Fig. 3; andshowing additional de- (Cl. its- 254) tails of construction of themotor-operated mechanism; and

Fig. 5 is a diagrammatic view orthe motoro'perated mechanism and controlcircuits which may be used for controlling its operation. 5

Referring now particularly to Figs. 1 and 2 of the drawings, therererenee character l0 des'' ignates generally a circuit breaker havingfixed contact members H and I2 and a movable contact member I 3 mountedwithin a suitable tank It. Since the circuit breaker l0 constitutes nopart of the invention,- it will be understood that the particularembodiment thereof illustrated in the drawings is provided solely forthe purpose of describing the invention more fully.

In order to operate the movable contact member' l3 into engagement withthe fixed contact membrs' I i and II, a motor I5 is provided which mayoi the polyphase squirrel-cage type. As illustrated; the motor i5 ismounted underneath a connecting mechanism; shown generally at ii,- the'housing I? of which may be moimted di-' rec'tly on the tank It bywelding or otherwise. The motor i5 provided with a' drive shaft f8extending into the connecting mechanism It where it is connected to a,"smart H which is rotatably mounted therein, as will be more fullydescribed hereinafter;-

Ilft' 10; carrying the movable contact member I3; is" connected tothehe'iiagonal shaft l9, by means of a link 2i, operating l ver 22comprising oppositely extending arms 23 and 24 link 25, and arm 2 6,which is secure to the Shaft i9 illustrated; the o erating level I! is"mounted for" rotation on a shaft 2T. It will also be observed that adepending' arm Ill is attached and an accelerating spring 29 isconnected between the arm 28 and a fl'xed pin" 30* in eraer to morerapidly meet the opening of the-contact membe s or the circuitbreakerl0.

As will be set forth hereinafter, the anti 2 is caused" to slightlyovertravel after the arm members of the" circuit breaker i0 are closedinf order to provide for deiener'gizirig the motor l5 after itis certainthat the'contact members have 0 been closed and latched in" thisposition; With' a view to reducing the incident to the stopping of theconnecting mechanism, a bore spring 35 is provided and mounted on asuitable 50 bolt 3G which is slidably mounted, as illustrated, in ablock-31.

In the event" that it is desired to close the circuit breaker 10'manually, ahandle (not shown) may be inserted in a socket 3| which maybe integrally formed with the upper arm 24 of the operating lever 22.

A tripping mechanism, shown generally at 38, is provided having adashpot 39 of the customary type, for controlling the time of operationof the tripping device. The details of connection and operation of thetripping device 38 will be set forth hereinafter. It will be noted,however, that the tripping device 38 includes a tripping winding 40surrounding an armature 4|, Fig. 2.

In order to more clearly describe the invention, the connectingmechanism 16 in Fig. 1 has been illustrated with its parts in theposition which they assume when the contact members of the circuitbreaker H] are in the open position. In Fig. 2, the connecting mechanismI6 is illustrated in a position corresponding to the closed condition ofthe contact members of the circuit breaker l5.

With particular reference to Fig. 2 of the draw ings, it will beobserved that the upper operating arm 24 is provided with a shortintegrally formed lever arm 43 to which a connecting link 44 is attachedfor operating an auxiliary switch 45. The connecting link 44 isconnected to a suitable operating arm 46 mounted on a shaft 41 of theauxiliary switch 45.

In order to open the circuits which are closed for energizing the motor15 after the contact members of the circuit breaker I!) have been movedto a predetermined position, a limit switch, shown generally at 50, isprovided having a fixed contact member 51 and a movable contact member52, the latter being pivoted in a suitable U-shaped frame 53 on a pin54. It will be observed that the lower end of the movable contact member52 is provided with a roller 55 which is disposed in the path of a cam56 that is mounted on the shaft 19 and rotates therewith. A compressionspring 5'! is provided, as shown, for biasing the movable contact member52 into engagement with the fixed contact member 5|.

In the event that the circuit breaker Ill should be tripped immediatelyafter the closing operation has been initiated, and after the limitswitch 56 has been operated to the open position, it is desirable tomaintain the limit switch 50 in the open position so that the circuitbreaker II] cannot automatically reclose to perform what is commonlyknown as a pumping action. Therefore, a holding winding 58 is providedwhich is arranged to be energized, as will be set forth hereinafter,upon energization of the motor 15. When the movable contact member 52 isoperated to the open position by means of the cam 56, an armature 59mounted on the upper end of the contact member 52 is moved into themagnetic field generated by the winding 58 so that the contact member 52is held in the open position so long as the winding 56 is energized.

Referring now particularly to Figs. 3 and 4 of the drawings, a detaileddescription will be given of the connecting mechanism l6, which isproyided for causing driving engagement between the shaft 18 driven bythe motor l5 and the shaft l9 which is directly connected to the movablecontact member 13 of the circuit breaker l 0. For this connection, it isdesirable to provide means whereby this connection may be accomplishedwith a minimum expenditure of energy and at the same time insuring thatdirect and positive connection will be maintained during the closingoperation. It is also desirable to pro- ..vide for breaking theconnection between the driving shaft [8 and the driven shaft 19 at anytime while they are in driving engagement in order to prevent thecontact members of the circuit breaker In from closing, for instance ona short circuit, or for any other reason, making it desirable to breakthe driving connection. It is also desirable to provide for connectingthe motor l5 to operate the contact members of the circuit breaker Hi tothe closed position from any last position of the motor l5. That is, therotor of the motor I5 and the mechanism connected directly thereto neednot be in any particular position relative to the other parts of thedevice in order that the circuit breaker I!) may be opera-ted.

With the foregoing conditions in mind, a clutch, shown generally at 65,is provided of the band friction type. The clutch 65 comprises a drum 66which is mounted for rotation with the shaft l8. Surrounding the drum 66is positioned 20 a helical clutch band 61, the upper end or high torqueend, Fig. 4, of which is secured to a worm wheel 68 which is mounted forrotation around the drum 66. A worm 69 is mounted on the motor shaft l8and in engagement with the worm wheel 68 for driving it.

The clutch band 61 is provided in the form of a helix around the drum 66with a slight clearance therebetween for gripping the drum 66 when thelower end or low-torque end, Fig. 4, is held with respect to the drum66. When a relatively slight force is applied to the low-torque end ofthe clutch band 61, it immediately grips the drum 66, therebysuccessively causing the succeeding turns of the clutch band 61 toengage the drum 66. Due to the frictional engagement between thesucceeding turns of the clutch band 61 with the drum 66, only arelatively slight force is required to hold the band6l in drivingengagement with the drum 66, while a relatively large torque may betransmitted from the Worm wheel 68 to the drum 66.

Since only a relatively slight torque need be applied at the low-torqueend of the clutch band 61, the cross-sectional area of the turns may begradually diminished, as illustrated, from the high-torque end to thelow-torque end, as will be readily understood.

In order to provide the slight torque which is required for operatingthe clutch 65, an electromagnetic clutch, shown generally at 13, of theface plate type is provided. The face plate 14 is secured to thelow-torque end of the clutch band 61 and mounted for rotation around theshaft l9 through the provision of a suitable bush- 5. ing 15. Theelectro-magnetic clutch 13 also comprises a winding-housing clutch plate16 which is mounted for rotation with the shaft I9, and carries awinding H in a suitably recessed opening in the face.

It will be observed that, as long as the winding IT remainsde-energized, the face plate 14 will be free to rotate around the shaft19, together with the clutch band 61 and the worm wheel 68, as driven bythe worm 69. However, as soon as 65 the winding H is energized, furtherrelative movement of the face plate 14 with respect to the shaft I9 isarrested, thereby causing the lowtorque end of the clutch band 61 toengage the drum 66 with the result that the remaining turns 70 of theclutch band 61 are brought into frictional engagement with the drum 66and causing the shaft [9 to be rotated to operate the circuit breaker IDto the closed position.

In order to hold the contact members of the circuit breaker I0 in theclosed position, a latch pivotally mounted on a suitable shaft 8| isprovided having a recessed portion 82 disposed to engage a roller 83,which is carried by the plate 16, of the electro-magnetic clutch 13. A-

coil spring 84 is provided for biasing the latch 80 into engagement withthe roller 83. Since the roller 83, which is caused to engage the latch80, is mounted on the clutch plate 15, which in turn is fixed on theshaft I 9 for rotation therewith,

it will be understood that the movable contact member I3 of the circuitbreaker I0 will be held in engagement with the fixed contact members IIand I2, since the shaft I9 is directly connected to the lift rod 20through the lever arrangement, which has been previously described.

With a view to tripping the circuit breaker I0 to the open position, alatch arm 85 is secured to the shaft 8I so that movement thereof causesa corresponding movement of the latch 80. As illustrated, the latch arm85 extends inwardly underneath the band friction clutch 65 and into thepath of movement of a cross piece 86 carried by a cradle member 81,which is pivotally mounted about a shaft 88. The cradle member 81 isprovided with an additional cross-piece 89, which is positioned in thepath of movement of the armature 4I. It will be understood, therefore,that the cradle member 81 will be moved in a clockwise direction onenergization of the tripping winding 40, thereby causing the latch arm85 and latch 80 to be moved in a counter-clockwise direct-ion, andremoving the recessed portion 82 of the latch 80 from engagement withthe roller 83 and permitting the contact member I3 of the circuitbreaker I0 to be moved to the open position under the combined influenceof the forces of gravity and the accelerating spring 29.

It will be understood that additional tripping mechanisms 38 may beprovided having additional armatures 4| for engaging the cross-piece 89of the cradle member 81 in the event that it is desirable to control thetripping of the circuit breaker I0 in response to other conditions notset forth in this specification, as will be readily understood.

Referring now particularly to the diagram illustrated in Fig. 5 of thedrawings, it will be observed that the circuit breaker I0 is providedfor connecting sections of power conductors 9I, 92 and 93 together. Itwill be also observed that a switch, as shown generally at 94, isprovided for connecting the windings of the motor I5 to the conductors9|, 92 and 93. While the main power circuit may be used to supplycurrent for operating the motor I5, it will be readily understood thatany other suitable source of power may also be used.

A protective relay, shown generally at 95, .is provided having anenergizing winding 95 arranged to be energized from the secondarywinding 91 of a current transformer. While the protective relay 95 isillustrated as being responsive to current flow in the power conductors,it will be readily apparent that its operation may be controlled inresponse to any other variable factor in the transmission system, as maybe desired.

A rectifier 98 of the copper-oxide type may be provided for supplyingdirect-current for energizing the winding I1 of the electro-magneticclutch 13.

In operation, assuming that it is desired to close the circuit breakerI0, the close switch I9I is depressed, thereby energizing the winding 11of the electromagnetic clutch 13 and winding I09 of the switch 94through the rectifier 98.

The circuit for energizing the winding 11 of the electro-magnetic clutch13 may be traced from the energized conductor 9! through conductor I02,contact members I03 of the closed switch IOI, conductor I04, contactmembers I05 of the protective relay 95, which are normally closed,

conductor I06, contact members 5I and 52 of the limit switch 50,conductor I01, rectifier 98 and conductor I08 to energized conductor 92.The circuit connections between the winding 11 and the rectifier 98 areobvious.

It will be observed that the winding I09 of the switch 94 is connectedin parallel circuit relation with the rectifier 98, and, therefore, itis unnecessary to trace the circuit whereby it is energized.

As soon as the switch 94 is operated to the closed position, thewindings of the motor I5 are energized, thereby causing it to rotate theshaft I8. The winding 11 of the electro-magnetic clutch 13 beingenergized, the band friction clutch is operated to directly connect theshaft I8 to the shaft I 9, and as a result the circuit breaker I0 isoperated to the closed position.

When the circuit breaker I0 is in the fully closed position, the slightovertravel permitted by the linkage between the shaft I9 and the liftrod 20 is sufficient to permit the cam 56 to engage the roller 55,thereby causing the contact members 5| and 52 of the limit switch 50 tobe opened against the force of the biasing spring 51. These contactmembers are held in the open position by means of the winding 58, whichis energized on the operation of the closed switch IOI over an obviouscircuit.

As soon as the circuit breaker I0 has been closed, the switch IOI may bereleased. This action, however, only de-energizes the winding 58, themotor I5 and the winding 11 of the electro-magnetic clutch having beende-energized through the opening of contact members 5| and 52, as willbe readily understood.

In the event that a short circuit should exist on any of the conductors9i, 92 or 93, causing a flow of current in the winding 96 of theprotective relay 95 beyond a predetermined amount, the contact membersI05 thereof will be opened and contact members IIO will be closed. Theopening of contact members I05 immediately causes the de-energization ofboth the motor I5 and the winding 11 of the electro-magnetic clutch 13provided they are energized, thereby permitting the contact members ofthe circuit breaker I0 to be immediately operated to the open position.This then provides what is known as trip free operation.

If the circuit breaker I0 has been completely closed and latched beforethe occurrence of the fault, the closure of the contact members III)completes a. circuit for energizing winding 40 of the tripping device38, thereby releasing the latch from engagement with the plate 16 of theelectro-magnetic clutch 13 and permitting the circuit breaker I0 to beopened, as willbe readily understood.

The circuit for energizing tripping winding 40 may be traced fromenergized conductor 9|, through conductors I02 and III, contact membersIIO of the protective relay 95, conductors H2 and H3, winding 40,conductor II4, contact members II5 of the auxiliary switch 45, andconductors H6 and I08 to energized conductor 92.

In the event that it is desired to manually trip the circuit breaker ID,the trip switch H1 may be operated. Since the contact members I 18 ofthe trip switch I I! are connected in parallel circuit relation with thecontact members H0 of the protective relay 95, it is unnecessary totrace again the circuit for energizing the tripping winding 40 onoperation of the trip switch I ll.

Since certain further changes may be made in the above construction, anddifferent embodiments of the invention may be made without departingfrom the scope thereof, it is intended that all matter contained in theabove description or shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

We claim as our invention:

1. A circuit interrupter comprising, in combination, relatively movablecontact members disposed to open and close an electrical circuit, amotor for operating said contact members to the closed position, a bandfriction clutch interposed between said contact members and said motor,and an electro-magnetic clutch disposed to effect the operation of saidband friction clutch to provide driving connection between said motorand said contact members.

2. A circuit interrupter comprising, in combination, relatively movablecontact members disposed to open and close an electrical circuit, amotor for operating said contact members to the closed position, a bandfriction clutch interposed between said contact members and said motor,a latch disposed to automatically hold said contact members in theclosed position, and an electromagnetic clutch disposed to effect theoperation of said band friction clutch to provide driving connectionbetween said motor and said contact members.

3. A circuit interrupter comprising, in combination, relatively movablecontact members disposed to open and close an electrical circuit, amotor for operating said contact members to the closed position, contactmeans for controlling the operation of said motor, a closing mechanismconnected directly to said contact members and disposed to provide aslight overtravel for operating said contact means to deenergize saidmotor on closure of said contact members, a band friction clutchinterposed between said closing mechanism and said motor, a latchdisposed to automatically engage with said closing mechanism during saidovertravel period, and an electromagnetic clutch disposed to effect theoperation of said band friction clutch to provide driving connectionbetween said motor and said closing mechanism.

4. A circuit interrupter comprising, in combination, relatively movablecontact members disposed to open and close an electrical circuit, amotor for operating said contact members to the closed position, and aband friction clutch and an electro-magnetic clutch disposed in seriesrelation between said contact members and said motor to effect drivingconnection therebetween.

5. A circuit interrupter comprising, in combination, relatively movablecontact members disposed to open and close an electrical circuit, amotor, and a band friction clutch and an electromagnetic clutch disposedin series relation between said contact members and said motor foreffecting driving connection therebetween to operate said contactmembers to the closed position, said electro-magnetic clutch beingdisposed at the low-torque end of said band friction clutch whereby onlya relatively small force is required to effect said driving connection.

6. A circuit interrupter comprising, in combination, relatively movablecontact members disposed to open and close an electrical circuit, a 5

motor, a band friction clutch comprising a drum directly connected tosaid contact members and a helical band disposed around said drum andhaving the high-torque end directly connected to said motor, and anelectro-magnetic clutch disposed between the low-torque end of said bandand said drum for effecting driving connection therebetween, therebypermitting said motor to operate said contact members to the closedposition. 15

7. A circuit interrupter comprising, in combination, relatively movablecontact members disposed to open and close an electrical circuit, amotor, a band friction clutch interposed between said contact membersand said motor, an electro- 20 magnetic clutch of the face plate typedisposed to effect the operation of said band friction clutch to providedriving connection between said motor and said contact members foroperating them to the closed position regardless of the last posi- 25tion of the motor, and circuit means for connecting said motor and saidelectro-magnetic clutch to a source of electric power.

8. A circuit interrupter comprising, in combination, relatively movablecontact members dis- 30 posed to open and close an electrical power cir.cuit, a motor for operating said contact members to the closed position,a band friction clutch interposed between said contact members and saidmotor, an electro-magnetic clutch disposed to effect the operation ofsaid band friction clutch to provide driving connection between saidmotor and said contact members, circuit means for connecting said motorand said electro-magnetic clutch to a current source, and relay meanscon- 4 nected to be responsive to the occurrence of a fault in saidpower circuit for deenergizing said electro-magnetic clutch, therebysubstantially instantaneously disconnecting said contact members fromsaid motor. 43

9. A circuit interrupter comprising, in combination, relatively movablecontact members disposed to open and close an electrical power circuit,a motor for operating said contact memhere to the closed position, aband friction clutch 5o interposed between said contact members and saidmotor, an electro-magnetic clutch disposed to effect the operation ofsaid band friction clutch to provide driving connection between saidmotor and said contact members, circuit means for connecting said motorand said electro-magnetic clutch to a current source, a latch disposedto automatically hold said contact members in the closed position,electrical means for tripping said latch to release said contact membersfor move- 60 ment to the open position, and relay means con nected to beresponsive to the occurrence of a fault in said power circuit forsimultaneously deenergizing said electro-magnetic clutch, therebysubstantially instantaneously disconnecting said 65 contact members fromsaid motor in the event said electro-magnetic clutch is not alreadydeenergized, and energizing said electrical means for tripping saidlatch in the event said latch has operated to hold said contact membersin 70 the closed position.

10. A circuit interrupter comprising, in combination, relatively movablemain contact members disposed to open and close an electrical circuit, amotor for operating said contact members to the closed position, a bandfriction clutch interposed between said main contact members and saidmotor, an electro-magnetic clutch disposed to effect the operation ofsaid band friction clutch to provide driving connection between saidmotor and said main contact members, circuit means for connecting saidmotor and said electro-magnetic clutch to a source of electrical energy,a switch for controlling the operation of said circuit means to energizesaid motor and clutch on closure thereof and anti-pumping means operablewhen said contact members have been operated to a predetermined positionfor preventing a second closure thereof until said switch is releasedand again closed.

11. A circuit interrupter comprising, in combination, relatively movablemain contact members disposed to open and close an electrical circuit, amotor for operating said contact members to the closed position, a bandfriction clutch interposed between said main contact members andtsaidmotor, an electro-magnetic clutch disposed to effect the operation ofsaid band friction clutch to provide driving connection between saidmotor and said main contact members, circuit means for connecting saidmotor and said electro-magneticclutch to a source of electrical energy,a switch for controlling the operation of said circuit means to energizesaid motor and clutch on closure thereof, and anti-pumping meanscomprising normally closed auxiliary contact members connected in seriescircuit relation with said circuit means and disposed to be opened whenthe main contact members of the circuit interrupter are moved to apredetermined position, thereby opening the energizing circuit for saidmotor and said clutch, and a holding winding disposed to be energized onclosure of said switch for maintaining said auxiliary contact members inthe open position as long as said switch remains in the closed position.

LEONARD B. CHUBBUCK.

GEORGE R. WISHART.

K. L. LIGAARD JEPPESEN.

